Apparatus for making a tubular article



y 1970 H. R. ALBREKTSON 3,518,906

APPARATUS FOR MAKING A TUBULAR ARTICLE Original Filed March 29, 1965 5 Sheets-Sheet 1 as T HELGE RAGNAR ALBREKTSON as MELVILLE, STRASSER, FOSTER 0nd HOFFMAN 6W y 170 H. R. ALBREKTSON ,518,?

APPARATUS FOR MAKING A TUBULAR ARTICLE Original Filed March 29, 1965 5 Sheets-Sheet 2 HELGE RAGNAR ALBREKTSON 5%, Melville, Stresser. Foster and 12' 42a Hoffman W,

Juiy 7, 1970 H. R. ALBREKTSON APPARATUS FOR MAKING A TUBULAR ARTICLE S SheetS-Sheet 5 Original Filed March 29, 1965 R W m G N M A O K a E E m Wm H, w fi H A a a J m MN W Qw M MN a w 8 4 3 N Q mm *m 0 N 0 a. \3 N \w 3 mm mm ow .7 WW mm mw uw and Hoffman I y 7, 1970 I H. R. ALBREKTSON 3,518,90

APPARATUS FOR MAKING A TUBULAR ARTICLE Original Filed March 29, 1965 I 5 Sheets-Sheet A 22 i a l:

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5 Sheets-Sheet 5 Win/I01? HELGE RAGNAR 5y ALBREKTSON Melxille.Strosser, Foster and Hgffmon Arrow em United States Patent O1 ice 3,518,906 Patented July 7, 1970 US. Cl. 83-1 11 Claims ABSTRACT OF THE DISCLOSURE Apparatus for forming semi-cylindrical articles wherein a cutting means having several parallel straight blades is inserted between two blocks of cutable material which are in substantially face-to-face contact and the cutting means i is rotated with respect to the blocks about an axis parallel to the blades.

CROSS REFERENCE TO RELATED APPLICATION This is a division of application Ser. No. 443,466, filed Mar. 29, 1965, now having the amended title Method of Forming a Tubular Article.

BACKGROUND OF THE INVENTION This invention relates to tubular articles comprised primarily for an expanded, cellular rigid form, and to an apparatus for producing such article.

It is believed that a complete understanding of the invention will be facilitated by a discussion in terms of a specific article, but it is to be understood that no limitations are to be inferred thereby, except insofar as specifically set forth in the claims appended to this specification.

It is well known that, particularly in industrial installations, insulation of both high and low temperature pipes and conduits is very essential. According to the prior art, this insulation has been accomplished in a number of ways, the simplest of which involves simply wrapping an insulating material, such as asbestos, above the pipe or conduit, and holding the insulating material in place with suitable covering such as tape, glue, paint, and so on. It is also known that the recently developed expanded, cellular rigid foams, such as for example, urethane, are admirably suited for insulating purposes. Inasmuch as the foam is essentially rigid when expanded, utilization of such a rigid foam for insulating pipes, conduits, and the like requires that the expanded foam be shaped in some manner so that it can be applied to the pipe. At the very least, this means that the foam must have a central opening of a size and shape sufficient to accommodate the pipe or the like to be insulated. It of course follows that both for economy of space, material, and weight, a cylindrical or tubular insulating structure is the most efiicient for cylindrical pipe.

Accordingly, it is a primary object of this invention to provide a tubular article consisting essentially of a rigid, expanded foam which can be more easily utilized than any structure or article heretofore available. While this tubular article is well suited for pipe insulation, it will also be understood that in certain cases, it can be used in and of itself to form a hollow conduit or the like.

More specifically, it is an object of this invention to provide a tubular article which may be disassembled into a plurality of substantially identical units; and which may be easily and quickly reassembled, the various components holding themselves together without the need of additional binding, tape, or the like.

One of the most important objects of this invention is to provide a means for simultaneously cutting a block of material into a plurality of nested tubular articles.

A further specific and important object of this invention is to provide a saw means comprising a plurality of saw or cutting elements so arranged as to enable a block of material to be cut into a plurality of nested tubular elements in a single actuation of the means through rotation thereof.

Still another object of this invention is the provision of an apparatus which is readily adjustable, and which can be utilized to produce tubular articles of any desired dimensions.

SUMMARY OF THE INVENTION In its broadest aspect, the apparatus of this invention contemplates a cutting means including a plurality of parallel, spaced apart blades. This cutting means is placed between a pair of blocks of cuttable material which are held in substantially face-to-face contact. The cutting means is then rotated through substantially 180 about its axis, in order to produce one or more tubular articles.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view showing a pair of rectangular blocks of expanded, rigid foam, prior to the beginning of the process of this invention.

FIG. 2 is an end elevational view showing one of the rectangular blocks of FIG. 1 after the completion of the first step of the process of this invention, the material removed being shaded.

FIG. 3 is a partial perspective view of the cutting apparatus of this invention.

FIG. 4 is an end elevational view showing a pair of blocks formed as shown in FIG. 2 assembled.

FIG. 5 is a partial perspective view showing diagrammatically a further step in the operation of the method of this invention.

FIG. 6 is a side elevational view showing the final forming apparatus of this invention.

FIG. 7 is a perspective view showing a plurality of nested tubular articles from one end.

FIG. 8 is a perspective view showing the other end of the nested articles shown in FIG. 7.

FIG. 9 is a front elevational view of one apparatus by means of which the method of this invention can be carried out.

FIG. 10 is a front elevational view of a modification of the invention.

FIG. 11 is a side elevational view of the apparatus of FIG. 10.

FIG. 12 is an exploded view of one embodiment of a device for holding the serrated blade of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1 through 6, the operative steps of the method of this invention will now be described. In FIG. 1, the starting material is a pair of blocks of a suitable material such as urethane foam indicated at 10 and 11. These blocks are generally rectangular in form, with the height dimension 10a being very slightly more than one-half the width 10b. These blocks may themselves have been cut from larger buns of the material. And the material is not to be restricted to urethane; other materials may be used depending on their characteristics, their availability and the end use to which the finished product is to be put.

Each of the individual blocks 10 and 11 is then passed through a form milling machine, to produce the surface configuration shown in FIG. 2. (The material removed by this operation is indicated by the shading.) More specifically, this operation will produce a central, semi-cylindrical, longitudinal recess 12, the tongues or tabs 13, 14, 15 and 16, and the grooves or recesses 17, 18, 19, and 20.

It will of course be understood that the recess 12, the tongues 13-16 and the grooves 17-20 all extend the full length of the blocks and 11. It will further be apparent that the surfaces of the block on opposite sides of the central recess 12 are mirror images of each other. That is, as shown more clearly in FIG. 4, a pair of blocks 10 and 11, each having been passed under the same milling cutters, may be placed in face-to-face interlocking relation, the tongues of one block being received in the grooves of the other. (In FIG. 4, the recess, grooves, and tongues of the block 10 have been given the same reference numerals used in FIG. 2 for the block 11, with the addition of the prime sign.)

FIG. 3 shows in perspective one form of cutting means suitable for use in this process. It includes a central bar or support 21, and the transverse blade mounting arms 22 and 23. The arms 22 and 23 can be secured to the support 21 in any suitable fashion, as by the threaded end and nut 24. Extending between the arms 22 and 23 are a plurality of thin, parallel spaced apart saw blades. The blades above the support 21 in FIG. 3 have been designated 25, 26, 27, and 28, while those below the support 21 have been given similar reference numerals with the addition of the prime sign. It should be apparent that each pair of blades is equally spaced from the center of the cutting means itself. It should also be noted at this time that each of the blades is adjustably mounted on the arms 22 and 23. The purposes and advantages of this feature will be explained in more detail hereinafter.

In the next step of the operation of the process of this invention, the cutting means, including the support, the blade mounting arms, and the blades, will be placed between a pair of blocks such as 10 and 11. At this time, it will be apparent that the central support 21 will lie within the recess 12, 12 while the blades 25-28, 25'-28' will lie between the mating sets of tongues and grooves discussed above.

When thus assembled, the entire cutting means is reciprocated in a direction parallel to its longitudinal axis defined by the central support 21. While being so reciprocated, the entire assembly will be rotated 180. That is, the central support 21 will reciprocate and rotate within the recess 12, While the various saw blades will cut the circular lines indicated by the reference numerals 25a- 28a and 25b-28b in FIG. 5. When the sawing operation has been completed, it will be seen that four nested, concentric tubular articles indicated at 29-29, 30-30, 31-31 and 32-32 have been produced. The only leftover material is the four corner portions indicated at 33 and this may, in the case of insulation material, be used for filling crevices and the like, with or without further shaping.

According to the preferred method of operation of this invention, the final operation may be performed by the apparatus shown in FIG. 6. This apparatus consists of the cutter bars 34 and 35, provided respectively with the cutting blades 36 through 39 and 40 through 43. Each of these arms 34 and 35 will be driven in rotation by a suitable source of power such as the motors indicated schematically at 44 and 45. This cutting apparatus is rotated about an axis concentric with the axis of the nested tubing, and moved into opposite ends of the nested tubular articles. As is best seen by comparing FIGS. 7 and 8, this will provide mating sets of circular tongue and grooves on opposite ends of the tubular articles.

While the preferred form of the invention contemplates the formation of the circular tongue and grooves as a last operation, it is feasible, and in some cases useful, to cut these tongues and grooves while the assembled blocks are still square in cross-section, such as shown in FIG. 4. In this manner, it may be easier to hold the blocks stationary while a cutting operation takes place.

Referring now to FIGS. 7 and 8, it will be seen that the above briefiy described method produces a nested series of tubular articles, each of which is composed of two substantially identical elements designated 10a-11a, 1017-111), 100-110, and 10d-11d. As explained earlier in this specification, the individual blades are adjustably mounted on the rotatable cutting member, in order that the inside and outside diameters of the various tubular articles can be set for any desired dimensions. For example, using starting blocks which when placed in faceto-face relation defined a square approximately 16" on a die, it would be possible to produce an inner tubular article having an inside diameter of 2" and an outside diameter 4", a second article having an inside diameter of 4" and an outside diameter of 8", another article having an inside diameter of 8" and an outside diameter of 10'', and an outermost article having an inside diameter .of 10" and an outside diameter of 16". Thus, if a particular job calls for a tubular article having an inside diameter of 10" and a wall thickness of 3 (an outside diameter of 16") the starting stock in cross-section must be a. square at least 16" on a side. According to prior art practices, everything removed to form the inside diameter-of 10" would be considered scrap. By virtue of the method of this invention, it is possible to produce three additional tubular articles having various inside diameters, so that very little stock is wasted.

It will also be seen in FIGS. 7 and 8 that each of the tubular articles is interlocked together by at least one mating tongue and groove. For example, the innermost article includes the grooves 17 and 17' and the mating tongues 13 and 13'. Accordingly, it will be apparent that in the original four milling operations in which the various tongues and grooves are formed, it will be necessary to coordinate the spacing of the tongues and grooves so that at least one mating tongue and groove will be located between successive pairs of the blades when the two blocks are assembled as shown in FIGS. 4 and 5.

The circular tongues and grooves formed on the ends of the nested articles by the cutters shown in FIG. 6 can also be seen in FIGS. 7 and 8. That is, the end shown in FIG. 7 includes the circular grooves or recesses 36a, 37a, 38a, and 39a, cut respectively by the cutters 36-39. Similarly, the end shown in FIG. 8 includes the circular grooves or recesses 40a, 41a, 42a, and 43a, cut respectively by the cutters 40-43. It will be clearly apparent to the skilled worker in the art that these circular tongues or grooves in opposite ends of the article mate; the circular tongue 50 (formed between the grooves 40a and 41a) will be received in the groove 36a, when a pair of tubular articles are placed in end-to-end relation. Similarly, the circular tongue 51 will fit in the circular groove 37a, the tongue 52 in the groove 38a, and the tongue 53 in the groove 39a.

In the preferred embodiment of the invention, the variout tongues and grooves will be so sized that a forced fit is necessary to place them together. Therefore, when installing the tubular articles of this invention as insulation over a given pipe, a pair of individual elements can be placed around the pipe and forced in face-to-face relation, with the tongues received by a forced fit in the mating grooves. These two elements will thus be held in position, at least temporarily. A second pair of semi-cylindrical elements can then be placed aroung the pipe in the same manner, and then joined in end-to-end relation with the first mentioned set of elements. The installation of course proceeds in this manner until the entire tubular structure has been completed, at which time a more permanent fastening can be effected if desired.

Turning now to FIG. 9, one embodiment of the invention has been shown in front elevation, with the cutting operation in progress (the cutting assembly has been rotated The apparatus includes the support frame 60 which includes the bearings 61, 62, 63, 64. Slidably and rotatably received in these bearings are the shafts 65 and 66 respectively, which are in effect extension of the central support 21 of the cutting means.

The free end of the shaft 66 will be connected to a suitable means for reciprocating the entire cutting assembly. Reciprocation can be accomplished by motor driven Pitman Motion, pneumatic or hydraulic cylinders, electric solenoid or solenoids, mechanical cam action, or with anultrasonic transducer. Inasmuch as these various methods for accomplishing reciprocation are entirely conventional, and do not form any part of the instant invention, they have not been shown inthis particular figure.

In order to achieve balance for the entire assembly, the arm 67, pivotally mounted at 68, is secured to the shaft 66 as at 69. Pivotally mounted on the other end of the arm 67 is the shaft 70, slidably mounted in the bearings 71 and 72, and carrying the counterweight 73.

A number of material supports, each including the upstanding arms 74 and 75, and the channel shaped crosspiece 76 are provided. The minimum requirement would be two such material supports, located as shown at diametrically opposed corners of the assembled blocks. It is of course within the scope of this invention to provide more or different material support means, it only being necessary that these supports securely hold the blocks of material together, and hold the blocks stationary while the saw assembly is being rotated. (Conceivably, however, the blocks could be reciprocated instead of the saw assembly, if desired.)

Rotation of the saw assembly may be accomplished in a variety of ways. At the present time, manual rotation by means of the crank 77 has been found entirely satisfactory. It will be seen that the crank 77 is keyed to the shaft 65 as at 78 to permit reciprocation of the saw assembly as such assembly is rotated by means of the crank. If desired, it would be relatively easy to provide mechanical or automatic means for turning the cutting assembly 180.

FIGS. and 11 show in front and side elevations, respectively, another modification of the apparatus of this invention. It will be immediately apparent that in this modification, the cutting means is operated on a generally vertical axis.

This embodiment includes the support frame indicated generally at 80 which mounts the bearings 81, 82, and 83. These bearing again slidably and rotatably receive the shafts 84 and 85 on the ends of the cutting means. Rotation of the cutting means and shafts is once again manually accomplished, this time by the handle 86, which will be keyed to the shaft 85 in the manner described in connection with the earlier embodiment.

No discussion has been made thus far of the nature of the cutting blades 25-28, and it is in fact contemplated that various cutting means, some requiring reciprocation and some not, may be utilized. For example, these cutting blades could simply be a straight, thin knife edge, a heated wire, or one of various types of saw blades, such as very thin, flat saw blades, special blades with a transverse curvature built into them, or a round saw wire.

The embodiments of the invention shown in these figures are particularly adapted for use with a saw type blade, which cuts in one direction only. As is clearly shown in FIGS. 10 and 11, the lower end of the shaft 85 is journaled in a thrust bearing 87, which rides on the cam 88. This cam is driven in rotation by the motor 89, the pulleys 90 and 91, and the belt 92. It will be apparent that this cam serves to force the entire saw assembly upward. It is therefore preferred that the blades 25-28 be oriented to cut on the upstroke. Gravity alone will then be sufficient to effect a return or downward stroke of the entire saw assembly. (Spring means, however, may be employed to aid such return, if necessary.) It will also be noted that a counterweight 93 may be effectively mounted on the same shaft with the cam 88 to counterbalance the assembly.

In this embodiment of the invention, the starting blocks of material are held in place by the vacuum boxes 94 and 95, which are substantially identical. Each of these vacuum boxes is fixedly secured to a pair of shafts 96 and 97, journaled in suitable bearings 98 for sliding movement. The shafts 96 and 97 will be connected to a suitable cylinder (either hydraulic or pneumatic-not shown) by means of which the vacuum boxes: can be moved from the position shown in FIG. 10 to a position in which the blocks of material secured thereto are brought into faceto-face contacting relation. Each of the vacuum boxes 94 and will also be connected to a suitable vacuum pump (not shown).

In operation of this embodiment of the invention, a pair of suitable material (for example the blocks 10 and 11 shown in FIGS. 2 and 4) are placed on opposite sides of the cutting means, and adjacent respectively the vacuum boxes 94 and 95. At this point, the vacuum pumps are put into operation, and the blocks will be securely held in position. Upon actuation of a suitable switch, the vacuum boxes 94 and 95 will move toward the center, bringing the blocks into face-to-faoe contacting relation. It should be understood that once this relationship is achieved, the inward force applied to the vacuum boxes is released, and they are held statically in this position. In other words, the blocks are held stationary, but are no longer forced toward each other. At this time, the saw unit begins its reciprocation, and is rotated 180 by means of the crank 86. It is believed important in this embodiment of the invention that the inward force not be applied once the cutting operation has begun. That is, the continued application of such force would tend to close the cuts made by the cutting blades, and may cause sufficient friction and binding to prevent the downward or return stroke of the saw unit by gravity alone. This problem could, of course, be overcome by the addition of spring means or the like to accomplish the downward stroke, as earlier indicated, but by means of the operation of the vacuum boxes just described, no such additional force has been found necessary.

Referring briefly to FIG. 12, the preferred device for holding the serrated cutting blades has been illustrated. By Way of explanation, it will be understood that when utilizing very thin saw blades, securely holding these blades under tension is somewhat difiicult. According to conventional practice, the ends of the blades are provided with slots or apertures into which mounting pins or the like fit; however, especially when utilizing very thin blades, this tends to weaken the blade. Accordingly, the blade clamp shown in FIG. 12 includes a support block 100 adapted to fit in the slot seen in FIG. 3 in the blade mounting arms 22 and 23. At the upper end of the block 100 is the bar 101 which spans the slot, and prevents the block 100 from being withdrawn therethrough.

The lower end of the block 100 is provided with the recess 102 of a width substantially the size of the saw blade to be utilized. A portion of the recess 102 is enlarged as at 103 to a total recess width substantially equal to twice the width of the saw blade.

In order to secure a blade in the recess 102-103, a short portion of the blade (perhaps even a scrap) indicated at 104 is placed in the enlarged portion 103 with its teeth pointing in the opposite direction from that which the teeth of the saw blade 105 itself are pointed. The blade portion 104 abuts a shoulder 103a atone end of the recess, the depth of the recess 103 being substantially equal to the thickness of the blade portion and/or blade. The blade portion 104 also engages a shoulder 103b at the side of the recess 103, the relationship among the recess 103, shoulders 103a and 103b, and the blade portion 104 being such that, when the blade portion 104 Within the recess portion 103 abuts the shoulders 103a and 103b, the teeth of the blade portion 104 will project beyond the end of the shoulder 103a into the recess portion 102. The blade 105 is then placed in recess 102 with its teeth engaged with the teeth of the portion of the blade 104. The interdigitating relationship of the teeth of the blade 105 and the portion of the blade 104 provide a very secure grip against axial tension along the saw blade. The two pieces 104-105 may be held in place in any suitable manner, as by the cover plate 106 and the mounting screws 107 and 108.

An additional advantage of this facet of the invention is that these elongated saw blades may be made in any desired or convenience lengths and then simply cut to the size required for any particular job. Conventional blades come in specified lengths with spaced holding holes having a fixed distance between centers; the blades of this invention do not have to be made with such preciseness and, therefore, may be manufactured more economically. And at the same time increased overall strength and holding power are achieved.

It is believed that the foregoing constitutes a full and complete disclosure of this invention. It will be apparent to the skilled worker in the art that numerous modifications and changes may be made without departing from the scope and spirit of this invention. For example, the apparatus and method are not limited to the forming of urethane; other foams or any similar material, or even soft wood (i.e., balsa) can be cut. Accordingly, no limitations are intended except insofar as specifically set forth in the following claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Apparatus for forming tubular articles comprising:

(a) cutting means including a plurality of parallel,

spaced apart blades;

(b) means for holding a pair of blocks of cuttable material in face-to-face relation with said cutting means therebetween; and

() means for rotating said cutting means with respect to said blocks about an axis parallel to said blocks.

2. The apparatus claimed in claim 1 wherein said cutting means includes an even number of blades arranged in pairs, the blades of each pair being equally spaced from said axis of said cutting means.

3. The apparatus claimed in claim 2 including means adjustably mounting said blades whereby the spacing of said blades from said axis of said cutting means may be varied.

4. The apparatus claimed in claim 3 wherein said cutting means includes a central, longitudinal support, and a pair of transverse blade mounting arms fixed thereon, said blades being adjustably secured between said arms.

5. The apparatus claimed in claim 4 wherein said means for rotating said cutting means with respect to said blocks is operative to rotate said cutting means through 180'.

6. The apparatus claimed in claim 5 wherein said blades are serrated, and including means for reciprocating said cutting means during said rotation relative to said blocks.

7. The apparatus claimed in claim 1 wherein said means for holding a pair of blocks of cutable material comprise a pair of vacuum boxes, means for exhausting the air from said vacuum boxes, means for moving said vacuum boxes toward each other, and for holding said blocks in face-to-face relation with said cutting means therebetween, without inward force.

8. Apparatus for forming tubular articles comprising:

(a) cutting means having a longitudinal axis and at least two blades on each side of said axis, said blades being parallel to each other and defining substantially a single plane;

(b)'means for holding a pair of blocks of cuttable material in face-to-face contacting relation with said cutting means therebetween; and

(0) means for rotating said cutting means with respect to said blocks about said longitudinal axis whereby to produce at least two nested sets of tubular articles, each said article comprising a pair of identical elements.

9. The apparatus claimed in claim 8 wherein said longitudinal axis of said cutting means is vertically oriented.

10. The apparatus claimed in claim 3 wherein said means adjustably mounting said blades includes a support block having a recess adapted to receive an end of one of said blades, a portion of said recess being enlarged to receive a serrated gripping blade, a gripping blade disposed in said enlarged portion of said recess, and an end of said first named blade disposed in said recess, the serrations of said blade and said gripping blade being in interdigitating relationship.

11. The apparatus claimed in claim 10 including means for holding said blade and said gripping blade in said recess and enlarged portion thereof respectively.

References Cited UNITED STATES PATENTS 1,765,161 6/1930 Kaempf et al 14375 X 2,609,048 9/ 1952 Samans et al. 83-1 2,898,955 8/1959 Schwartz 14377 X 3,332,459 7/1967 Gilmore l43l71 X FRANK T. YOST, Primary Examiner US. Cl. X.R. 

